Changelog validation should fail if an "Uncategorized" heading is present anywhere

[MajorLift]

Example

  ## [8.0.2]

- ### Uncategorized
+ ### Changed

  - Bump TypeScript version to `~5.0.4` and set `moduleResolution` option to `Node16` ([#3645](https://github.com/MetaMask/core/pull/3645))
  - Bump `@metamask/utils` from `^9.0.0` to `^9.1.0` ([#4529](https://github.com/MetaMask/core/pull/4529))

MetaMask/core@cc09e4e#diff-e535ad89313f51c5a789b8f3abc6c1f8537bf7930087b9d6a9b16e6fdc28af89R12